Cryptography Research wants piracy speed bump on HD DVDs

[Bill Frantz]

On 1/5/05, Marcel_Popescu at microbilt.com (Marcel Popescu) wrote:
>Why not the way it happens right now - re-encoding? Few people post DVD
>images of movies on p2p networks, and even when they do, I prefer a DivX or
>XviD variant. (Much better given my 'net bandwidth.) I strongly doubt
>there's any chance of a watermark surviving an unknown re-encoding process
>(DivX has dozens of parameters you can change).

What I have heard from the people building watermark systems is:

(1) The system requirements are that the water mark repeat every few seconds to mark every part of the work being watermarked.  Some systems encrypt the watermark in each repeat block with a different, repeat-block dependent key.

(2) By using error correction codes, a short sequences of bits, like a serial number, can be encoded to survive re-encoding.  The claim is that you have to do serious damage to the quality of the work before the serial number becomes unreadable.


Removing the water mark may be quite difficult, but any professional movie thief would find the business expense of new players quite affordable.  Some individuals might decide that giving a bunch of movies to their friends from an about-to-be-retired player was a reasonable thing to do.  Someone who works in a store might use an off-the-shelf player.  And ...  Once a copy gets into circulation, it could spread quite widely.

Cheers - Bill

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